Echo cs 590,600,620 porting/mod/build thread

[paragonbuilder]

I do those carbs a few different ways. I can block off all the factory fuel supplies, and add my own. Or I can leave some of them open. It depends on how much fuel the engine needs.

Depends how far you take the build?


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[Mastermind]

Exactly

 

[jake wells]

you done with my saw yet? its getting cold here and need some wood cut.

 

[Red97]

you done with my saw yet? its getting cold here and need some wood cut.

Your husky 365 blow up???

 

[jake wells]

Your husky 365 blow up???

nope just out of gas.

 

[Red97]

The main feed is through the bleed on top with the L side. There is also a passage from the L into the H also then the feed into the main jet for delivery.
David had an idea of closing the main jet off which would divert everything through the lower side passages......not a bad idea.....and would be easy to do compared to closing off the H bleed hole.

That makes sense now..

Stock carb would Rev higher if you chose to sacrifice a good low end tune. With the H needle seated I could get 5-800 more slightly leaning the Low.

Think im going to study the a HDA 203 (670 carb) Then attempt to copy it with the stock carb. Hopefully save a bunch of random guessing.

 

[Mastermind]

I'm watching...

 

[Red97]

@Poleman

According to my very crude observation..

I believe @David Young was on to something.

The 670 carb has the same high/low outlet. (That we tried restricting). But dosent have the hole in the bottom of the main.

Still have to test it out, but I opened the jb hole to 1mm closest micro drill I had to stock. And pressed in a main jet out of another hda without the hole...

We shall see. Everything on the metering side looked the same with the exception of the main. The 670 main had a thin cone shaped main, a screen, clip then a plug. It was smaller od so I couldn't just press it into the 590 carb.

 

[Mastermind]

Post pics of the carb details please Joe.

 

[Red97]

Stock 590 left 670 right.

Where the 590 main is a solid brass piece 1 hole in the bottom, 1 in the side and 1 out the top along with a rubber check valve at the top.

The 670 right, has a long tapered main 1 hole stright through. Goes about mid way into the venturi of the carb.

Has a screen a clip to keep the screen from blocking off flow then the brass plug to seal it off so the high needle has control over the fuel amount.

 

[Mastermind]

Have you thought about swapping throttle shafts into a HDA191?

 

[Mastermind]

The HDA199

 

[jake wells]

the carbs look identical can you swap the brass plugs or no?

 

[Red97]

Have you thought about swapping throttle shafts into a HDA191?

Briefly. Jut the main from one for now...

The HDA199

View attachment 35187

Similar to the 191


That is a 1 before the 4
#faststockcarb



Seems blocking the hole in the bottom of the main will do the trick. In my case replace the main with a solid bottom jet.

don't think H/L those holes need to be restricted.

L is around 1.25 out and H is around 1

 

[Mastermind]

So......you just swapped the main nozzle out of a 199? Nothing else needed?

 

[David Young]

Briefly. Jut the main from one for now...



Similar to the 191


That is a 1 before the 4
#faststockcarb



Seems blocking the hole in the bottom of the main will do the trick. In my case replace the main with a solid bottom jet.

don't think H/L those holes need to be restricted.

L is around 1.25 out and H is around 1

Does this mean I get a best answer?

Glad it was easy for you.

 

[Red97]

So......you just swapped the main nozzle out of a 199? Nothing else needed?

191 but yes. I believe the same could be achieved by just blocking the hole in the stock nozzle.

I did epoxy the one hole Poleman and I discussed earlier. But drilled it back to 1 mm. I do no believe that is needed. As both carbs 590/670 have the same diameter h/l holes

Does this mean I get a best answer?

Lol, I guess.
Glad it was easy for you.

 

[Mastermind]

You can get Walbro parts here.

http://vepetersen.com/

419-838-5911

You might have to get the nozzles 5 - 10 at a time for them to bother selling to you.

 

[Four Paws]

Does this mean I get a best answer?

Regardless, you can feel good about yourself!

 

[Red97]

670 venturi



590.

Think the Shorter one is a better design anyway, Carb feels a lot more "crisp" than with the 670 carb.